The death toll is still rising from the Ebola virus in West Africa, with health experts calling it the worst outbreak of the disease the world has ever seen.

Ebola has killed nearly a thousand people in four West African countries. But a doctor working in the heart of the outbreak told CBS News many cases are going unreported.

"This outbreak of Ebola is remarkable. The cases in the last couple of weeks represents a third of all the Ebola cases ever reported," said Dr. Michael Phillips, director of Infection Prevention and Control at NYU Langone Medical Center.

The virus is spinning out of control because it's difficult to contain in a sprawling, congested city center. The bodies of Ebola victims litter the streets in some areas.

On record, there are now more than 1,700 active cases, including an elderly missionary priest who has been evacuated and returned home to Spain.

And some infected people are refusing treatment for fear of being mistreated in a health care system that has one doctor for every 100,000 people.

How easy is it to catch Ebola? Dr. Bogdan Neughebauer, an infectious disease specialist with the Sentara Medical Group in Virginia Beach, Va., talks about this and more with CBN News' Heather Sells.

The Centers for Disease Control and Prevention now has 24 staff members on the ground in West Africa.

Meanwhile, at the U.S. Africa leaders' summit in Washington, President Barack Obama called for even more health workers on the ground.

"This is not an airborne disease," he said. "This is one that can be controlled and contained very effectively if we use the right protocols."

The CDC is now on its highest alert, and the World Health Organization is considering whether to declare an international public health emergency.

Meanwhile, Dr. Kent Brantly and Nancy Writebol, the two American missionaries who contracted Ebola in Liberia, continue to receive treatment at Emory University hospital in Atlanta.

Efrem Graham

News Anchor & Reporter

Efrem Graham is an award-winning journalist, who comes to CBN News from the ABC owned and operated station in Toledo, Ohio. He received his master's degree from the Columbia University Journalism School. He also holds a bachelor's degree in English Literature from the Richard Stockton College of New Jersey. Follow Efrem on Twitter @EfremGraham and "like" him at Facebook.com/EfremGrahamCBN.